This meeting will bring together leading researchers in the fields of magnetism and superconductivity to explore new functionality in which spin, charge and superconducting phase coherence can work together. Their discoveries and predictions form the foundation for the field of superconducting spintronics which could eventually be developed as a replacement for large-scale semiconductor-based logic and memory.

The schedule of talks and speaker biographies are available below. Speaker abstracts will be available closer to the meeting. Recorded audio of the presentations will be available on this page after the meeting has taken place. Meeting papers will be published in a future issue of Philosophical Transactions A.

Poster session

There will be a poster session at 17:00 on Monday 25 February 2019. If you would like to apply to present a poster please submit your title, proposed abstract (not more than 200 words and in third person), author list, name of the proposed presenter and authors' institutions to the Scientific Programmes team no later than Monday 14 January 2019. Please include the text "Superconducting spintronics: poster abstract" in the subject heading. Please note that places are limited and are selected at the scientific organisers' discretion. Poster abstracts will only be considered if the presenter is registered to attend the meeting.

Attending this event

This is a residential conference, which allows for increased discussion and networking.

Professor Mark Blamire, University of Cambridge, UK

Mark Blamire is Professor of Device Materials in the Department of Materials Science at the University of Cambridge. He leads the Device Materials group, working primarily on superconducting spin electronics. This work is currently supported by an EPSRC Programme Grant (Superspin) exploring the potential for superconducting spin electronics. He is a Fellow of the Institute of Physics and the Institute of Materials, Minerals and Mining. He received his PhD in 1985 under Jan Evetts and has worked on the properties of superconducting materials and devices throughout his career. He has authored over 450 journal papers and contributed to the most recent European roadmap on superconductive electronics.

Dr Chiara Ciccarelli, University of Cambridge, UK

After her PhD in 2012, Dr Chiara Ciccarelli got a Junior Research Fellowship at Gonville and Caius College in Cambridge. In 2016 she was awarded a Winton Advanced Research Fellowship by the Cavendish Laboratory and since 2017 she has been a Royal Society University Research Fellow, running her own group on spintronics.

Professor Matthias Eschrig, Royal Holloway, University of London, UK

Matthias Eschrig is Professor of Physics and leads the Condensed Matter Theory group at Royal Holloway, University of London. He has a PhD from University of Bayreuth (1997) and obtained his Habilitation at Karlsruhe Institute of Technology (2005), after having spent time in USA at Northwestern University and at Argonne National Laboratory. He moved to UK in fall 2010. His research focuses on superconductivity, quantum transport in heterostructures, proximity systems, topological phenomena, as well as quantum many body theory and correlated electron physics. He is one of the leading international theorists on the interaction of superconductors and ferromagnets and co-founded the field of ‘Superconducting Spintronics’. He is Deputy Director of the Hubbard Theory Consortium and member of the Board of Governors of the NSF International Institute on Complex Adaptive Matter. In 2015 he was awarded the Lars Onsager Professorship and Lars Onsager Medal of the Norwegian University of Science and Technology.

Dr Jason Robinson, University of Cambridge UK

Jason Robinson read Materials Science at Imperial College London (2000-2004), then went on to a PhD at Cambridge University in 2004. In 2011, he was elected to a University Research Fellowship at the Royal Society and in 2015 was appointed a lecturer at Cambridge University then a Readership in 2016 in the Department of Materials Science. He leads a research group that focuses on understanding the fundamental properties of functional materials and spintronics, with major achievements including the discovery of spin-polarised triplet Cooper pairs, which led to the field of superconducting spintronics.

Professor Lesley Cohen, Imperial College London, UK

Professor Lesley Cohen is a professor of solid state physics studying the fundamental behaviour of materials and devices with unusual electronic, optical, superconducting or magnetic properties for a variety of applications including solid state efficient and environmentally friendly magnetic refrigeration. Over a number of years her group has developed a suite of characterisation tools that have enabled unique insight into the behaviour of materials at low temperatures and high magnetic fields. She has published over 350 journal publications in her areas of interest.

Professor Lesley Cohen, Imperial College London, UK

Professor Lesley Cohen is a professor of solid state physics studying the fundamental behaviour of materials and devices with unusual electronic, optical, superconducting or magnetic properties for a variety of applications including solid state efficient and environmentally friendly magnetic refrigeration. Over a number of years her group has developed a suite of characterisation tools that have enabled unique insight into the behaviour of materials at low temperatures and high magnetic fields. She has published over 350 journal publications in her areas of interest.

Dr Jagadeesh S Moodera, Massachusetts Institute of Technology, USA

Dr Jagadeesh Moodera is a senior research scientist and group leader at the physics department at MIT, USA. Jagadeesh is also a Distinguished Visiting Professor at the IQC, University of Waterloo; a Visiting Professor at the Applied Physics Department, Technical University of Eindhoven; a Distinguished Institute Professor at IIT Madras; and a Distinguished Foreign Scientist at NPL, Delhi. Jagadeesh has served on the Board of External Experts for national research programs in France, Holland, England and Ireland and has been elected a Fellow of the American Physical Society. He is also the recipient of several awards: IBM and TDK Research Awards, and the Oliver E. Buckley Condensed Matter Prize from the American Physical Society. Jagadeesh’s research interest lies in: 1) manipulating electron spin in solids-spin tunnelling, spin filtering and interfacial exchange coupling; 2) molecular spintronics: towards molecular-scale spin memory; 3) ferromagnet/superconductor heterostructure towards superconducting spintronics; 4) quantum transport in topological driven systems and heterostructures: atomic scale interface exchange phenomena; atomically resolved interface chemical/physical/magnetic studies; electrical transport; and 5) the search for Majorana bound states in unconventional superconductors, and interactions.

Dr Cecilia Holmqvist, Linnaeus University, Sweden

Cecilia Holmqvist is a postdoctoral research fellow at Linnaeus University, Sweden. She received her PhD at Chalmers University of Technology, Sweden, and subsequently was a postdoc at Konstanz University, Germany, and at the Norwegian University of Science and Technology, Norway. Her research interests include non-equilibrium charge and spin transport as well as noise in superconducting hybrid structures, in particular how Andreev states may interact with the dynamics of a nanomagnet. Her research interests also include spin-orbit torques and magnetisation dynamics generated by materials with strong spin-orbit coupling such as normal metals and topological insulators, and spin transport carried by classical spin-wave dynamics, such as spin superfluidity, in ferromagnets and antiferromagnets.

10:30-11:00Coffee

11:00-11:30Magnetic moment manipulation by a superconducting current in Josephson junctions

Professor Alexander Buzdin, University of Bordeaux, France

Alexander Buzdin is a full professor at the University of Bordeaux in France; since 2004 he has been a senior member of the prestigious Institut Universitaire de France, where he holds the Chair “Physics of Superconductivity”. This year Alexander is the Liverhulme Trust professor at the Material Science Department of Cambridge University. Alexander graduated from Moscow State University and then habilitated in 1986. He worked under the supervision of the Nobel Prize winner Alexey Abrikosov at the Institute for High Pressure Physics of Russian Academy of Science and Argonne National Laboratory. Alexander is the author of more than 250 articles on superconductivity, magnetism and nanophysics. He received the Holweck Medal and Prize in 2013, a joint award by the UK Institute of Physics and the French Physical Society, for his pioneering theoretical studies of superconductor–ferromagnet multilayer systems.

11:45-12:15

Professor Francesco Giazotto, National Enterprise for Nanoscience and Nanotechnolgy, Italy

Professor Matthias Eschrig, Royal Holloway, University of London, UK

Matthias Eschrig is Professor of Physics and leads the Condensed Matter Theory group at Royal Holloway, University of London. He has a PhD from University of Bayreuth (1997) and obtained his Habilitation at Karlsruhe Institute of Technology (2005), after having spent time in USA at Northwestern University and at Argonne National Laboratory. He moved to UK in fall 2010. His research focuses on superconductivity, quantum transport in heterostructures, proximity systems, topological phenomena, as well as quantum many body theory and correlated electron physics. He is one of the leading international theorists on the interaction of superconductors and ferromagnets and co-founded the field of ‘Superconducting Spintronics’. He is Deputy Director of the Hubbard Theory Consortium and member of the Board of Governors of the NSF International Institute on Complex Adaptive Matter. In 2015 he was awarded the Lars Onsager Professorship and Lars Onsager Medal of the Norwegian University of Science and Technology.

13:30-12:00Voltage-control over a high-field superconducting transition and the superconducting exchange interaction

Professor Jacob Linder, Norwegian University of Science and Technology, Norway

Abstract

Jacob Linder’s group predicts two interesting phenomena related to superconductivity in hybrid structures driven out of equilibrium by application of an electric voltage. Firstly, they theoretically demonstrate that superconductivity in thin films can be stabilised in high magnetic fields if the superconductor is driven out of equilibrium by a voltage bias. For realistic material parameters and temperatures, they show that superconductivity is restored in fields many times larger than the Chandrasekhar–Clogston limit. After motivating the effect analytically, they present rigorous numerical calculations to corroborate the findings, and discuss concrete experimental signatures. Secondly, Linder discusses how the magnetic exchange interaction in a spin-valve is influenced by non-equilibrium superconductivity. Linder shows that the sign of the exchange interaction in a spin-valve, determining whether a parallel or antiparallel magnetic configuration is favoured, can be controlled via an electric voltage. This occurs due to an interplay between a non-equilibrium quasiparticle distribution and the presence of spin-polarized Cooper pairs. These findings may be of relevance for spin-based superconducting devices which in practice most likely have to be operated precisely by non-equilibrium effects.

Professor Jacob Linder, Norwegian University of Science and Technology, Norway

Professor Jacob Linder, Norwegian University of Science and Technology, Norway

Membership status unknown

No primary institution

Jacob Linder is a professor of physics at the Center of Excellence QuSpin, Norwegian University of Science and Technology. He has taught several courses in quantum physics, particle physics, electromagnetism, and classical mechanics. His main research interests lie within the quantum physics of condensed matter, with particular emphasis on magnetic materials, superconducting materials, and Dirac materials. He has co-authored more than 100 peer-reviewed papers in internationally reputable journals such as Physical Review and the Nature family of journals. He lives in Trondheim (Norway) with his wife and two daughters.

14:15-14:45Comparison of the spin-transfer torque mechanisms in three terminal spin-torque-oscillators

Dr Emilie Jué, National Institute of Standards and Technology, USA

Abstract

The spin transfer torque is one of the most active field of spintronics due to its potential for use in memory and logic applications. This control can be achieved via a spin polarised current with the mechanism of spin-filtering torque (SFT) or through a pure spin current via the mechanism of spin-orbit torque (SOT). Over the past several years, SOT has gained increased attention due to the new possibilities that it offers for data storage applications. However, the quantification and comparison of both mechanisms’ efficiencies remains uncertain, due to the uncertainty in material parameters needed to quantify the torque. In this work, researchers at NIST compared for the first time the SFT and SOT efficiencies acting on the same nanomagnetic element. To do so, they created 3-terminal spin-torque oscillators (STO) composed of spin-valves (SV) patterned on top of Pt nanowires. The devices are excited either by SFT or by SOT depending on whether the current is applied through the SV or through the Pt wire. By comparing the magnetization dynamics obtained with the different STT mechanisms, they quantify the relative efficiencies of the SOT and SFT in the system as a function of the dimensions of the SV and Pt nanowires.

Dr Emilie Jué, National Institute of Standards and Technology, USA

Dr Emilie Jué is a research associate in the National Institute of Standards and Technologies within the Spintronics Group. She graduated with a PhD in Physics from the University of Grenoble in 2013 where she studied the current induced domain wall motion in ultrathin materials with high spin-orbit coupling. Her current research interests include spin-orbit torques and spin-torque oscillators. She is an active member of the IEEE society. She has authored and co-authored 10 peer reviewed publications that have been cited over 1000 times.

15:00-15:30Tea

Abstract

Ferromagnetic resonance is a powerful method to extract information on the magnetic torques, spin damping and magnetic anisotropies. In Chiara Ciccarelli’s group ferromagnetic resonance methods are applied to quantitatively evaluate the spin torques in asymmetric ferromagnets, magnetic insulators and synthetic antiferromagnets. The focus of this talk will be on some recent work where spin pumping experiments are conducted on HM/SC/FM and SC/FM structures (SC=niobium, HM=platinum and FM=permalloy). Ferromagnetic resonance in the permalloy is excited via a waveguide and the damping measured through the superconducting transition temperature of niobium. These results show that while in the SC/FM structures spin pumping is suppressed when the niobium turns superconducting, in the HM/SC/FM structures the presence of platinum leads to an enhanced spin transfer through superconducting niobium with respect to its normal state and even with respect to bare platinum.

Dr Chiara Ciccarelli, University of Cambridge, UK

After her PhD in 2012, Dr Chiara Ciccarelli got a Junior Research Fellowship at Gonville and Caius College in Cambridge. In 2016 she was awarded a Winton Advanced Research Fellowship by the Cavendish Laboratory and since 2017 she has been a Royal Society University Research Fellow, running her own group on spintronics.

Dr Machiel Flokstra, University of St Andrews, UK

Machiel Flokstra is a lead researcher in the Superconductivity and Magnetism group at the University of St Andrews. Machiel’s research interest is focused on exploring the complex interplay between conventional superconductivity and ferromagnetism using a variety of unique measurement techniques, in particular low-energy muon-spin spectroscopy. He did his PhD at Leiden University, under the supervision of Jan Aarts, on proximity effects in superconducting spin-valve structures.

Dr Hidekazu Kurebayashi, University College London, UK

Dr Hidekazu Kurebayashi is Associate Professor in the Electronic & Electric Engineering department at UCL and leads the spintronics group in the London Centre for Nanotechnology. He is an expert of spin transport and spin current physics, probed by a variety of on-chip and cavity microwave techniques to excite spin dynamics. After the completion of his PhD at Cambridge in 2010, he carried on his academic career at the Cavendish Laboratory first as a postdoctoral researcher, and then as JSPS and JST research fellows, before the appointment of a lectureship at UCL in 2013.

Dr Sebastian Bergeret Material Physics Center (CFM-CSIC), Spain

Sebastian Bergeret is the head of the Mesoscopic Physics Group at the Material Physics Center in San Sebastian, Spain. His research field is the theoretical study of transport properties of nanostructures, focusing mainly on superconducting systems. Sebastian’s works provided significant insights on superconductivity in hybrid systems and has led to verifiable predictions. In particular, his works on odd-triplet superconductivity, and more recently on non-equilibrium and spin-orbit coupling in superconductors has sparked an intense research activity in the field and opened the door for spin-based applications of superconducting devices.

Abstract

Detlef Beckmann covers the experimental observation of spin-dependent thermoelectric effects in superconductor-ferromagnet tunnel junctions in high magnetic fields. The thermoelectric signals are due to a spin-dependent lifting of particle-hole symmetry on the energy scale of the superconducting gap. Due to the small energy scale, the thermoelectric effects can be quite large, and a maximum Seebeck coefficient of about 100 µV/K can be inferred from the data. The thermoelectric signals can be further enhanced by an exchange splitting induced by the proximity effect with a ferromagnetic insulator. The results directly prove the coupling of spin and heat transport in high-field superconductors, which also leads to nonlocal thermoelectric effects in multiterminal devices where several ferromagnetic wires are attached to a single superconducting wire via tunnel junctions. In these structures, heating one of the ferromagnetic wires leads to a nonlocal thermoelectric current in a remote wire, over distances of the order of 10 µm.

Professor Detlef Beckmann, Karlsruhe Institute of Technology, Germany

Detlef Beckmann obtained his PhD in Karlsruhe in 1997 on Fermi surface studies of organic superconductors. Since 1999, he has been a staff scientist at the Institute of Nanotechnology of the Karlsruhe Institute of Technology (KIT), where he has worked on molecular electronics, mesoscopic physics and superconductor-ferromagnet hybrid structures. In these structures, the competition of magnetism and superconductivity leads to new transport phenomena such as nonlocal Andreev reflection and triplet supercurrents. Recently, his work has been focussed on nonequilibrium transport in high-field superconductors, where coupled spin and heat transport leads to very long spin relaxation times and large thermoelectric phenomena.

10:30-11:00Coffee

Abstract

The researchers of RHUL propose a mechanism for the generation of pure superconducting spin-current carried by equal-spin triplet Cooper pairs in a superconductor (S) sandwiched between a ferromagnet (F) and a normal metal (Nso) with intrinsic spin-orbit coupling. They show that in the presence of Landau Fermi-liquid interactions the superconducting proximity effect can induce non-locally a ferromagnetic exchange field in the normal layer, which disappears above the superconducting transition temperature of the structure. The internal Landau Fermi-liquid exchange field leads to the onset of a spin supercurrent associated with the generation of long-range spin-triplet superconducting correlations in the trilayer. They demonstrate that the magnitude of the spin supercurrent as well as the induced magnetic order in the Nso layer depends critically on the superconducting proximity effect between the S layer and the F and Nso layers and the magnitude of the relevant Landau Fermi-liquid interaction parameter. Their results demonstrate the crucial role of Landau Fermi-liquid interaction in combination with spin-orbit coupling for the creation of spin supercurrent in superconducting spintronics.

Dr Xavier Montiel, Royal Holloway, University of London, UK

Dr Xavier Montiel is currently a post-doctoral research assistant in the Physics department in Royal Holloway, University of London. He is working on the microscopic theory which describes the thermodynamic, electronic and transport properties of the superconducting multilayers for superconducting spintronics. He has calculated the stabilization of spin current in superconducting heterostructure exhibiting spin-orbit coupling and Fermi Liquid interaction. Before this position, Xavier was a post-doc in CEA Saclay, France, where he worked on the theoretical description of the pseudogap phase of Cuprate Superconductors. He was a post-doc at the International Institute of Physics in Natal, Brazil, where he worked on the spin-liquid phase in Heavy Fermion compounds. He obtained his PhD at the University of Bordeaux on the proximity effect between Superconductor and Ferromagnet.

11:45-12:15Chiral spin interactions mediated by a supercurrent

Dr Irina Bobkova, Institute of Solid State Physics of RAS and Moscow Institute of Physics and Technology, Russia

Dr Irina Bobkova, Institute of Solid State Physics of RAS and Moscow Institute of Physics and Technology, Russia

Dr Irina Bobkova, Institute of Solid State Physics of RAS and Moscow Institute of Physics and Technology, Russia

Membership status unknown

No primary institution

Irina Bobkova graduated from Moscow Institute of Physics and Technology in 2001 and received her PhD in condensed matter physics from the Institute of Solid State Physics in 2004. Now she is a Senior Researcher at the Institute of Solid State Physics of RAS. Her research interests with published research are in the field of coexistence of superconductivity and magnetism, proximity effects at nanoscale, nonequilibrium superconductivity and low-dissipation spintronics. Also, she is a lecturer at Moscow Institute of Physics and Technology. She teaches courses on electron interactions in metals for master students and on the introduction to group theory for undergraduate students.

Dr Jason Robinson, University of Cambridge UK

Jason Robinson read Materials Science at Imperial College London (2000-2004), then went on to a PhD at Cambridge University in 2004. In 2011, he was elected to a University Research Fellowship at the Royal Society and in 2015 was appointed a lecturer at Cambridge University then a Readership in 2016 in the Department of Materials Science. He leads a research group that focuses on understanding the fundamental properties of functional materials and spintronics, with major achievements including the discovery of spin-polarised triplet Cooper pairs, which led to the field of superconducting spintronics.

Abstract

Josephson junctions containing ferromagnetic (F) materials are being developed for use in cryogenic random access memory. In principle, either the critical current amplitude or the ground-state phase difference across the junction could be used to store information. In the Northrop Grumman JMRAM memory architecture, the ferromagnetic junction acts as a passive phase shifter in a SQUID loop that also contains two SIS junctions. Phase control has now been demonstrated in two kinds of Josephson junctions: in a simple spin-valve device containing two ferromagnetic layers and in a more complex multi-layer device that carries spin-triplet supercurrent. In both types of devices, the ground-state phase difference can be controllably switched between 0 and π by reversing the magnetisation direction of one of the magnetic layers in the device. The physical mechanism by which the ground-state phase difference changes, however, is different in the two types of devices. Both types of devices require further optimisation to be suitable for large-scale superconducting memory arrays. This talk will review the physics underlying the behaviour of both types of ferromagnetic Josephson junctions, and discuss progress in optimising devices for use in cryogenic memory.

Professor Norman Birge, Michigan State University, USA

Norman Birge received his PhD in 1986 from the University of Chicago, studying the glass transition in supercooled liquids. He changed his focus to electronic transport during his post-doctoral work at AT&T Bell Laboratories. He came to Michigan State University in 1988 and has been there ever since, aside from two sabbatical years with the Groupe Quantronique at the CEA Saclay in France. His research has spanned several topics in quantum transport and mesoscopic physics, including 1/f noise and universal conductance fluctuations, dissipative quantum tunneling of defects in metals, electron phase coherence at very low temperatures, the superconducting proximity effect, and nonequilibrium phenomena in metallic systems. His current research focuses on the interplay between superconductivity and ferromagnetism in hybrid structures.

Professor Takashi Kimura, Kyushu University, Japan

Professor Takashi Kimura has been a Professor in the Physics Department at Kyushu University since 2013. From 2009 to 2013, Takashi was a Professor in Inamori Frontier Center at Kyushu University. Between 2004 and 2008, he was an Assistant Professor in the Institute for Physics at University of Tokyo. From 2002 to 2004, Takashi was a researcher in Riken Frontier System. Takaski received his PhD in Engineering from Osaka University in 2002.

Abstract

Superconducting rapid single flux quantum (RSFQ) logic is now used in radio frequency signal digital receivers. Sophisticated superconducting SFQ-based digital processors and memories are being developed for the next generation energy efficient data centres. Recently, RSFQ and its energy-efficient successor logics were used to realize classical control for quantum processors. Traditionally, control operations are performed at room temperature leading to scalability limitations and long latency in quantum operations. For scalable low-latency qubit control, the classical electronics should located as close to quantum chips as possible. Superconducting SFQ circuits proximally located to the quantum processor can be the technology of choice due to its low power (10-21 Joule to per switching at 20 mK). They can be engineered to produce the minimal back action to qubits. The ability to operate at very high speed (tens of gigahertz clock) opens a way for digitizing and fast processing qubit output data for error correction and generation of qubit control signals. Furthermore, hybrid systems integrating together the quantum and classical processing hardware units are envisioned to enable various application algorithms which typically combine quantum and classical algorithmic modules. The implementation of scalable quantum-classical 3D integrated system extending across multiple temperature stages will be discussed.

Dr Oleg Mukhanov, HYPRES Inc, USA

Oleg A Mukhanov is Chief Technology Officer at HYPRES, which he joined in 1991 to initiate the development of Rapid Single Flux Quantum (RSFQ) superconductor circuit technology. He obtained his PhD in physics from Moscow State University in 1987 and an MS in electrical engineering (with honors) from Moscow Engineering Physics Institute in 1983. Prior to Hypres, he was a staff scientist in Moscow State University where he co-invented RSFQ technology. At Hypres, Dr Mukhanov has initiated and led many projects on high-performance digital and mixed signal RSFQ circuits for variety of applications including data and signal processors, analog and time to digital converters, which resulted in the first commercial use of superconducting digital electronics – RSFQ-based Digital-RF receivers. Dr Mukhanov authored and co-authored over 170 scientific papers, book chapters and over 20 patents. Dr Mukhanov is a Fellow of IEEE and recipient of The IEEE Award for Continuing and Significant Contributions in the Field of Small Scale Applied Superconductivity.